Box blanks and boxes of cardboard or pasteboard



Jan. '19, 1965 B. u. 'ENG'STRGM 3,156,230

BOX BLANKS AND BOXES 'OF' CARDBOARD OR PASTEBOARD Filed March 18, 1965 United States Patent O 3,166,230 BOX BLANKS AND BOXES OF CARDBOARD R PASTEBOARD Bengt Urban Engstrom, Umea, Sweden, assrgnor to Per Sigurd Nes, Umea, Sweden Filed Mar. 18, 1963, Ser. No. 265,808 Claims priority, appiication Sweden Apr. 2, 1962 Claims. (Cl. 229-36) This invention relates to a creased box blank of cardboard or pasteboard, and to the box formed thereby. The blank for forming the closed and unglued box is cut out in one piece and is creased to include a rectangular bottom panel, a long side wall panel hingedly connected with a cover flap, a second long side wall panel including a top flap, and two short side wall panels including each a top fla The general object of the invention is to provide such a blank which may be readily folded by unskilled persons to form a rigid box, particularly intended for archive purposes.

Another object of the invention is to provide simple and still reliable corner locks including a slit and locking tongue connection.

These and other objects of the invention will appear from the following description of a preferred embodiment thereof shown by way of example in the accompanying drawing in which FIG. 1 is a plan view of a fiat box blank embodying the invention.

FIG. 2 is a perspective view of the box as erected from the blank in FIG. 1 but prior to closing the box by means of the cover flap.

FIG. 3 is a partial perspective view of the box when closed and standing upright on one of its short side walls, the box being viewed from the opposite side relative to FIG. 2.

FIG. 4 is a detail section along line 4-4 in FIG. 2 on an enlarged scale illustrating the locking tongue secured in a slit.

FIG. 5 is a fragmentary enlarged perspective view of one of the corners when the locking tongue is in a position in the slit just before its fully inserted position.

The blank shown in FIG. 1 comprises a single sheet of cardboard or pasteboard, cut to the shape shown. Crease lines 1 to 14 define a rectangular bottom panel 15, two long side wall panels 16, 17, two short side wall panels 18, 19 a cover flap 20 extended with a connecting portion 21 and a tapering locking flap 22, and three top flaps 23, 24, 25 provided as extensions of the short side wall panels 18, 19 and of the long side wall panel 17.

t each end of the short side wall panels 18, 19 are extensions forming support fiaps 26, 27.

In the bottom panel 15 is a straight slit 28 adapted to receive the tapering locking flap 22 which at its side edges may be provided with opposite recesses 29 adapted to engage the ends of slit 28 for securing the locking flap 22 Each top fiap 24, 25 of the short side wall panels 18, 19 is at its end adjacent the long side wall panel 17 provided with locking tongue 30 having an inner straight side edge 31 forming an angle 0 with the free edge portion of the top fiat. This angle is less than 90 degrees and preferably it is between 70 and 85 degrees. The free end edge of the locking tongue 30 is preferably in line with the crease line 1, as shown.

In the crease line 1 between the long side wall panel 17 and its top flap 23 are two slits 32, 32 for receiving the locking tongues 30, the distance 5 between the inner end of each slit to the adjacent end edge of the panel 17 being equal to or somewhat greater than the distance a between the inner end of side edge 31 and crease line 10,

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so that the locking tongue will fit snugly against the inner end of the slit.

The blank is folded to box form by raising the short side wall panels 18, 19 folding the support flaps 26, 27 inwardly, raising the long side wall panel 17 and folding its top flap 23 inwardly, and further by folding the locking tongues 30 to a position perpendicular to their top flaps 24, 25 and folding the same inwardly so that the tongues 30 will be inserted into the slits 32 and the ends of flaps 24 and 25 will overlap the ends of the flap 23.

The box is now ready for receiving the articles to be contained therein. The locking tongues are locked in position by frictional engagement at the tightly closed slits and further by the hook like engagement of the tongues with the ends of the slits. Pressure on the side walls tending to fold them outwardly which may for instance occur from heavy articles within the box, will not result in disconnection of the locking tongues.

Furthermore, as will be seen from FIG. 4, the locking tongues may rest with their end edges against the bottom 15 in order to contribute to the rigidity of the corner, and preferably the free side edge of the adjacent support flap 27 is parallel with and close to the inner side edge 31 of the tongue 30 to form an abutment therefor.

In the preferred embodiment of FIGS. 1 and 5, the inner side edge 31 of the locking tongue is inclined inwardly to form a hook like engagement of the end of slit 32, in order to obtain a safe lock.

What is claimed is:

1. A box blank of cardboard or pasteboard, having crease lines defining a rectangular bottom panel, a long side wall'panel extended beyond its outer margin with a cover flap, a second long side wall panel extended beyond its outer margin with a top flap, two short side wall panels, each of them being extended beyond its outer margin with a top fiap, a locking tongue integral with and extending outwardly beyond each end of said top flaps of said short side wall panels adjacent said second long side wall panel, each of said two locking tongues being spaced from the crease line across the junction of the adjacent top flap and its short side wall panel, two slits in the crease line across the junction of the said second long side wall panel and its top flap, each of said slits being spaced from the adjacent end edge of said top flap of said second long side wall panel a distance equal to the spacing of each of said locking tongues from said crease line across the junction of its adjacent top flap and its short side wall panel, said slits being disposed for receiving said locking tongues with their inner side edges engaging the outer ends of said slits, the inner edge of each of said locking tongues being substantially straight and standing at an angle of 70-85 degrees to the free portion of the end edge of its adjacent top flap.

2. A box blank as defined in claim 1, in which each of said locking tongues has an outer free end edge lying in line with a crease line across the junction between said second long side wall panel and its top flap.

3. A box made from a single creased blank of card board or pasteboard, comprising a rectangular bottom, two long side walls and two short side walls, one of said long side walls being provided with a cover flap and the other with a top flap, each of said short side walls having a top flap overlapping the top flap of said other long side wall, the overlapping end of each top flap of said short side walls being extended with a locking tongue spaced from the crease line of its associated short side wall and top flap and folded at right angles to its top flap and inserted into a slit made in but spaced from the end of the crease line defining the hinged connection between said other long side wall and its top flap, the free inner edge of said locking tongue engaging the adjacent end of said slit and extending backwards towards the adjacent corner of the box to form a hook like connection with the end of said slit, said lockingrtongues each forming an angle of 7085 with said top flap of said other long side wall.

4. A boX as defined in claim 3, in which said locking tongue has a free end edge resting on said bottom.

5. A box as defined in claim 3, in which each of said short side walls are atrtheir ends provided with support flaps extending between said bottom and said top flaps,

having each a free side edge extending in parallel with and close to the inner side edge of said locking tongue.

References Cited in the file of this patent UNITED STATES PATENTS Blackman May 31, 1910 Gebhart Sept. 19, 1916 Gordon Apr. 19, 1919 Lester June9, 1942 Gibbons Dec. 22, 1953 

1. A BOX BLANK OF CARBOARD OR PASTEBOARD, HAVING CREASE LINES DEFINING A RECTANGULAR BOTTOM PANEL, A LONG SIDE WALL PANEL EXTENDED BEYOND ITS OUTER MARGIN WITH A COVER FLAP, A SECOND LONG SIDE WALL PANEL EXTENDED BEYOND ITS OUTER MARGIN WITH A TOP FLAP, TWO SHORT SIDE WALL PANELS, EACH OF THEM BEING EXTENDED BEYOND ITS OUTER MARGIN WITH A TOP FLAP, A LOCKING TONGUE INTEGRAL WITH AND EXTENDING OUTWARDLY BEYOND EACH END OF SAID TOP FLAPS OF SAID SHORT SIDE WALL PANELS ADJACENT SAID SECOND LONG SIDE WALL PANEL, EACH OF SAID TWO LOCKING TONGUES BEING SPACED FROM THE CREASE LINE ACROSS THE JUNCTION OF THE ADJACENT TOP FLAP AND ITS SHORT SIDE WALL PANEL, TWO SLITS IN THE CREASE LINE ACROSS THE JUNCTION OF THE SAID SECOND LONG SIDE WALL PANEL AND ITS TOP FLAP, EACH OF SAID SLITS BEING SPACED FROM THE ADJACENT END EDGE OF SAID TOP FLAP OF SAID SECOND LONG SIDE WALL PANEL A DISTANCE EQUAL TO THE SPACING OF EACH OF SAID LOCKING TONGUES FROM SAID CREASE LINE ACROSS THE JUNCTION OF ITS ADJACENT TOP FLAP AND ITS SHORT SIDE WALL PANEL, SAID SLITS BEING DISPOSED FOR RECEIVING SAID LOCKING TONGUES WITH THEIR INNER SIDE EDGE ENGAGING THE OUTER ENDS OF SAID SLITS, THE INNER EDGE OF EACH OF SAID LOCKING TONGUES BEING SUBSTANTIALLY STRAIGHT AND STANDING AT AN ANGLE OF 70-85 DEGREES TO THE FREE PORTION OF THE END EDGE OF ITS ADJACENT TOP FLAP. 